Curved Runners - rule of thumb limit?

[Scott Thomson]

Hi everyone,

I'm currently working on modelling my runners to fit in side the chassis and have been contemplating a curved runner with basically no straight length.

My trepidation to this is how this will affect the effective length of the runner and if people have found a rule-of-thumb limit to what sort of radii and angles you want to be running. Our dyno is currently out of action so can't really do much to test some real examples.

My current design has two arcs - one of 120 degrees and another of 80 degrees with radii no less than 150mm for either. Is this too tight?

[Scott Thomson]

Hi everyone,

I'm currently working on modelling my runners to fit in side the chassis and have been contemplating a curved runner with basically no straight length.

My trepidation to this is how this will affect the effective length of the runner and if people have found a rule-of-thumb limit to what sort of radii and angles you want to be running. Our dyno is currently out of action so can't really do much to test some real examples.

My current design has two arcs - one of 120 degrees and another of 80 degrees with radii no less than 150mm for either. Is this too tight?

[Charlie]

Winterbone and Pearson has an equation for equivalent length. Don't have it handy as it's away in storage but I recommend it, a great book and lots of useful info like that.